FDA clears lifesaving feature for Google's Pixel Watch 3

The FDA has approved a key health feature of Google's Pixel Watch 3, almost six months after the wearable device was launched in the US.

The Loss of Pulse Detection feature can detect when a user's heart has stopped beating – for example, due to a cardiac arrest, respiratory or circulatory failure, overdose, or poisoning – and alert emergency services. It is the latest in a series of developments in the overlap between medical devices and consumer technology.

The feature has been available for European users of the smartwatch since the launch of the device last year, but had to be disabled in the US pending FDA approval. The rollout in the US is now expected to start at the end of March, according to Google.

The approval means Google's device can now offer something that is not yet available on the Apple Watch – which dominates the smartwatch market - although, the latter does have notifications for unusually high or low heart rate, as well as fall detection.

"Many loss of pulse incidents happen when the person is alone, leaving them with effectively no chance of receiving resuscitation," according to Google. "Loss of Pulse Detection on Pixel Watch 3 can detect loss of pulse and automatically place a call to emergency services, potentially saving lives."

The opt-in feature relies on using the device's optical heart rate sensor, which uses green light to check the user's pulse. If it detects signs of pulselessness, infrared and red lights also turn on, looking for additional signs of a pulse, while the motion sensor starts to look for movement.

An artificial intelligence algorithm then assesses the pulse and movement signals to confirm a loss of pulse event and, if it does so, triggers a check-in to see if the user responds. If they don't respond and motion is still not detected, the app triggers an audio alarm and countdown.

Finally, if there is still no response after the countdown, a call is automatically placed to emergency services with an automated message that says the user has no pulse and gives their location.

Other features on the watch include irregular heart rhythm notifications that can check for signs of atrial fibrillation, a Safety Check app that allows users to set a timer on devices when they feel unsafe and sends a location to a loved one if they don't respond, and software to detect falls and car crashes.

Google stresses that the detection is not perfect and is not intended for people with pre-existing heart conditions or those who require cardiac monitoring.